Hi all, When I compiled below test program using gcc version 4.1.2 20070925 (Red Hat 4.1.2-33) chain it is giving segmentation fault . *[naveen@localhost ~]$ ./test.out Segmentation fault* But the same program is compiled using -O3 flag it is not giving the segmentation problem. Plz can any one help to debug this problem?? //test.c #include<stdio.h> unsigned long FindCompoundSound(void* pPlayer, void* data, unsigned long dataLen, unsigned long* formats, unsigned short numFormats, void** csData, unsigned long* csDataLen) { unsigned long foundFormat = 1; unsigned short bestMatch = 0xFFFF; unsigned long FI_DeviceSound_CacheMask = 0xFFFF; unsigned char sData; unsigned long sFormat= 0xFF; unsigned long sLength; unsigned short i; for (i=0;i<numFormats;i++) { if ((formats[i] & FI_DeviceSound_CacheMask) == sFormat) { if (i < bestMatch) { bestMatch = i; foundFormat = formats[i]; if (csDataLen) { *csDataLen = sLength; } } } } } int main(void) { FindCompoundSound(NULL,NULL,1, NULL,1,NULL,NULL); return 0; } Regards, Raju G